WO2005119353A1 - Film reflechissant a diffusion pour eclairage de fond d’affichage a cristaux liquides - Google Patents

Film reflechissant a diffusion pour eclairage de fond d’affichage a cristaux liquides Download PDF

Info

Publication number
WO2005119353A1
WO2005119353A1 PCT/US2005/018613 US2005018613W WO2005119353A1 WO 2005119353 A1 WO2005119353 A1 WO 2005119353A1 US 2005018613 W US2005018613 W US 2005018613W WO 2005119353 A1 WO2005119353 A1 WO 2005119353A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
recited
layer
display apparatus
light guide
Prior art date
Application number
PCT/US2005/018613
Other languages
English (en)
Inventor
Xiang-Dong Mi
Ronald Joseph Sudol
Thomas Miles Laney
Original Assignee
Eastman Kodak Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Eastman Kodak Company filed Critical Eastman Kodak Company
Priority to JP2007515358A priority Critical patent/JP2008501149A/ja
Publication of WO2005119353A1 publication Critical patent/WO2005119353A1/fr

Links

Classifications

    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333Constructional arrangements; Manufacturing methods
    • G02F1/1335Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336Illuminating devices
    • G02F1/133615Edge-illuminating devices, i.e. illuminating from the side
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/02Diffusing elements; Afocal elements
    • GPHYSICS
    • G02OPTICS
    • G02FOPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333Constructional arrangements; Manufacturing methods
    • G02F1/1335Structural association of cells with optical devices, e.g. polarisers or reflectors

Definitions

  • a diffusive reflector film is described for use in enhancing light efficiency.
  • Light- valves are implemented in a wide variety of display technologies.
  • microdisplay panels are gaining in popularity in many applications such as televisions, computer monitors, point of sale displays, personal digital assistants and electronic cinema to mention a few applications.
  • Many light valves are based on liquid crystal (LC) technologies. Some of the LC technologies are prefaced on transmittance of the light through the LC device (panel), while others are prefaced on the light traversing the panel twice, after being reflected at a far surface of the panel.
  • An external field or voltage is used to selectively rotate the axes of the liquid crystal molecules.
  • the LC medium can be used to modulate the light with image information. Often, this modulation provides dark-state light at certain picture elements (pixels) and bright-state light at others, where the polarization state governs the state of the light.
  • the light from a source is selectively polarized in a particular orientation prior to being incident on the LC layer by an absorptive polarizer.
  • the LC layer may have a voltage selectively applied to orient the molecules of the material in a certain manner. The polarization of the light that is incident on the LC layer is then selectively altered upon traversing through the LC layer.
  • a display apparatus includes a light guide having at least two surfaces over which a substantially diffusively reflective layer is disposed.
  • the substantially diffusive reflective layer has a reflectivity of at least 94% and a diffusitivity of at least 97%.
  • a method of transmitting light to a display includes providing a light guide, and diffusively reflecting light e from at least two surfaces of the light guide.
  • Fig. 1 is a cross-sectional view of a liquid crystal display device in accordance with an example embodiment.
  • Fig. 2 is a perspective three-dimensional view of a light guide in accordance with an example embodiment.
  • Fig. 3 is a conceptual representation showing diffuse and specular reflection as they may apply to example embodiments.
  • Fig. 4 is a cross-sectional view of a light guide in accordance with an example embodiment.
  • Fig. 5 is a tabular representation showing the normalized illuminance from an output surface of a light guide having a variety of reflective surfaces according to an example embodiment.
  • a diffusive reflective film is disposed over a light guide to improve the illumination level at a light valve, which is illustratively a LC panel.
  • the light guide receives light from a light source at one surface, and transmits light to the LC panel via another surface.
  • Diffusively reflective dots are disposed along a surface that is opposite to the surface that transmits the light to the LC panel.
  • a diffusively reflective layer which is described more fully herein, is then disposed over at least one of the remaining surfaces of the light guide.
  • a specularly reflective layer may be disposed over at least one reflective surface of the light guide and/or about the light source.
  • Fig. 1 is a cross-sectional view of a light- valve imaging device 100 of an example embodiment.
  • the imaging device 100 includes a transmissive light- valve 101, which is illustratively an LC panel.
  • a backlight assembly includes a polarization selective reflector 102, a brightness enhancement layer 103 and a diffuser layer 104.
  • the backlight assembly provides a uniform light distribution to the light valve 101, with an angular distribution of light that is designed to meet the angular field of view required by an end-user.
  • a laptop computer with a brightness enhancement layer has a viewing angle that is typically on the order of approximately +_20 degrees off-center axis.
  • Beneath the diffuser layer 104 is a light guide 105, which is coupled to at least one light source 106.
  • the light guide 105 has a diffusive reflector layer 107 disposed over at least a one surface.
  • layer 107 is disposed over a bottom surface 108 and a side surface 110 of the light guide 105.
  • the diffusive reflector layer 107 is beneficially disposed on all surfaces of the light guide 105, except the transmissive surface 111 opposite the bottom surface, and the surface 113, which is coupled to the light source 106.
  • layer 107 has an index of refraction that is substantially the same as or greater than an index of refraction of the light guidel05.
  • layer 107 has an index of refraction that is less than an index of refraction of the light guide 105.
  • the light source 106 includes a reflector 114, which serves to improve the intensity of the light coupled from the light source to the light guide 105.
  • the reflector 114 is a specular reflector of the light.
  • the lamp reflector 114 can be of a metallic layer such as aluminum or a non-metallic specular reflector film such as NikuitiTM Enhanced Specular Reflector (ESR) film with over 98.5% reflectivity.
  • ESR Enhanced Specular Reflector
  • specular and diffuse reflection are described in detail below.
  • the light source 106 is one of: cold cathode fluorescent lamp (CCFL); a light emitting diode (LED) or an array thereof; an organic LED or array thereof; or an ultra-high pressure (UHP) gas lamp or other source of randomly polarized white light.
  • the light source 106 is coupled to the light guide and light 112 is optimally transmitted via surface 111.
  • light 112 is randomly polarized and may be transmitted through surface 111 toward the light valve 101. Alternatively, light 112 may be transmitted back through surface 111 after reflection r from elements of the backlight assembly, the brightness enhancement layers 103, or the polarization selective reflector 102. This light 112 may then be recycled and re-transmitted. This recycling is useful in improving the light efficiency. Moreover, the diffusive reflection from the light guide provides randomly polarized recycled light.
  • the material from which the light guide 105 is formed may be a polymeric material such as polycarbonate, polystyrene, polymethyl methacrylate (PMMA), or other methacrylates, acrylates, acetates for the intended purposes of the example embodiments.
  • an air gap 120 between the layer 107 and the lower surface 108 of the light guide 105.
  • This air gap 120 in combination with reflective dots or microstructures (not shown) on the lower surface 108 fosters a more uniform output from the light guide to the LC panel 101, and thus to the image plane (not shown). It is noted that the air gap 120 assists in the frustration of waveguiding by the light guide 105. Finally, it is noted that no affirmative measure must be made to effect the air gap 120. To wit, the air gap 120 will exist between the layer 107 and the light guide 105 unless remedial steps are taken to prevent the gap 120 (e.g., the use of an index matching layer between the layer 107 and the light guide).
  • the layer 107 may be disposed over the side surfaces as desired using an optical adhesive layer that has an index matching property. This adhesive (not shown) will foster the diffuse scattering of the light, and prevent the (specular) reflection of light and thus waveguiding by the light guide. Because it is beneficial to provide diffuse light to the light valve 101, light 112 traverses the optional diffuser layer 104. It is emphasized that the diffuser layer 104 is optional since the diffusive reflection provided by the layer 107 of the example embodiment is sufficient to provide the requisite diffusivity of the light.
  • a layer 107 is a diffusively reflecting layer described in co-pending application serial numbers 10/719,762 and 10/954,003, entitled “Highly Reflective Optical Element,” and “Highly Reflective Optical Element”, respectively, both of which are assigned to the present assignee.
  • the disclosure of this application is specifically incorporated herein by reference.
  • specularly reflecting films including metallic or multilayer films, known to one of ordinary skill in the art, may be used.
  • VikuitiTM Enhanced Specular Reflector (ESR) film manufactured by Minnesota Mining and Manufacturing, Incorporated, may be used as such a specular reflector.
  • ESR Enhanced Specular Reflector
  • the light 112 traverses the brightness enhancement layer 103.
  • the brightness enhancement layer 103 beneficially provides light in a prescribed angular distribution 115 to the selectively reflective polarizer 102.
  • the brightness enhancement layer 103 redirects light (through recycling) that would be otherwise lost, and unobserved at the image screen because it is too far off axis to contribute to the image.
  • light 116 that is oriented in an undesirable trajectory to be on- axis at the viewing screen is reflected.
  • the brightness enhancement layer 103 is a commercially available element.
  • the brightness enhancement layer may be a VikuitiTM Brightness Enhancement film, which is offered by Minnesota Mining and Manufacturing, Incorporated, as well as other known films that enhance brightness in display applications.
  • Light 115 is transmitted to the reflective polarizer 102, which transmits light 117 of a first polarization state and reflects light 118 of a second polarization state, which is orthogonally polarized relative to the first polarization state.
  • the reflective polarizer may be one of a variety of reflective polarizers well known to one of ordinary skill in the optical arts.
  • the transmitted light 117 of the first polarization state is essentially linearly polarized along the transmission axis of a polarizer 122 disposed beneath the light valvelOl.
  • the reflected light 118 of the second polarization state which is essentially linearly polarized along the absorption axis of the polarizer 122, thus is reflected and avoids being absorbed by the polarizer 122.
  • the light valve 101 is illustratively an LC panel. LC materials are widely used for electronic displays.
  • an LC panel 101 is situated between a polarizer (e.g., polarizer 122) and an analyzer 123, and the LC material has a director exhibiting an azimuthal twist through the layer with respect to the normal axis.
  • the analyzer 123 is oriented such that its absorbing axis is perpendicular to that of the polarizer 122.
  • Incident light polarized by the polarizer 122 passes through a liquid crystal cell and may be transformed to a polarization state that is substantially orthogonal to its polarization state at incidence to the LC cell 101. As is known, this polarization transformation is dependent on the molecular orientation in the liquid crystal, which can be altered by the application of a voltage across the cell.
  • the transmission of light from an external source can be controlled to form an image.
  • the transmitted light 117 is incident on the polarizer 122 and the light valve 101, which modulates the light incident thereon and transmits light 119 that forms the image (not shown).
  • dark pixels are formed by selective absorption by the analyzer 123 after the selective transformation of the polarization state of the light 115 to be substantially parallel to the absorption axis of the absorber.
  • the reflected light 116 and 118 are at least partially transmitted back through surface 111 of the light guide 105.
  • the reflected light 116 and 118 are then incident on at least one of the surfaces of the light guide 105.
  • the layer 107 is disposed over at least two of the surfaces (e.g., surfaces 108, 110) of the light guide 105. Moreover, dots (not shown in Fig.l) are disposed over the bottom surface 108, and optionally over selected sides of the light guide 105. According to the example embodiments, the reflected light 116, 118 is diffusively reflected by the layer 107 and the dots. Among other affects, this reflection causes light 121 to be randomly polarized. As referenced previously, this randomly polarized light may then be transmitted through the surface 111. Thereby, the light reflected by the brightness enhancement layer 103 by the reflective polarizer 102, and by the light valve 101, all of which would have been lost, is transmitted back through the surface 111.
  • Fig. 2 is a perspective view of the light guide 105 according to an example embodiment.
  • the rectangular parallelpiped shown is merely illustrative of the geometric shape of the light guide 105.
  • the light guide 105 also may be a prism, a regular polyhedron or a polyhedron.
  • more than one light guide may be used.
  • the light guide 105 may be of other shapes than those explicitly referenced in order to improve the efficiency of light to the light valve and thus the image surface.
  • the layer 107 is disposed over surfaces 108, 110, 201 and 202 of the light guide 105. It is noted that the layer 107 is not disposed over the surface 111 or surface 113, which are the top or transmissive surface, and the surface to which the light source couples, respectively.
  • the layer 107 disposed thereover.
  • the diffusive reflective layer 107 disposed over these four surfaces of the light guide 105 and a specularly reflective layer about the light source 105 (e.g., layer 114).
  • the diffusive reflective layer 107 disposed over all four surfaces 108, 110, 201, 202.
  • the layer is necessarily disposed over the surface 108 and at least one other surface.
  • the layer 107 may be omitted from surface 110, and a second CCFL or other suitable device with a reflector similar to 114 may be used.
  • a second CCFL or other suitable device with a reflector similar to 114 may be used.
  • the second light source or additional light sources may be disposed over other surfaces of the waveguide in lieu of the layer 107 may be used.
  • Fig. 3 illustrates the properties of a reflector. To wit, light 301 is incident on the surface 302 of a reflector at an angle of incidence ( ⁇ ) relative to a normal to the surface 303.
  • specular reflection occurs when the angle of reflection (IT) equals the angle of incidence (IT), as shown at 304.
  • the term specular reflection applies to incident light 301 that is reflected within a cone 305 that is approximately + 10 degrees from the direction 304.
  • the reflector is a diffusive reflector when the incident light 301 is reflected from the surface of the reflector 302 at an angle outside the cone 305.
  • diffusively reflective surfaces beneficially obey Lambert's cosine law, which states that the reflected luminous intensity in any direction from an element of a perfectly diffusing surface varies as the cosine of the angle between that direction and the normal vector (normal 303) of the surface.
  • the luminance of that surface is the same regardless of the viewing angle.
  • this law described matte surfaces.
  • many surfaces including white dots have some percentage in specular reflection, and some percentage in diffuse reflection.
  • An ideal Lambertian reflector has 100% diffuse reflection, and 0% specular reflection. It is understood that a reflector has a high percentage of diffuse reflection is a good candidate as a Lambertian (or diffusive) reflector in example embodiments.
  • the layers 107 disposed on the surfaces of the light guide 105 and reflector 114 may be diffusively reflective or specularly reflective.
  • the layers 107 of the example embodiments are beneficially diffusively reflective materials.
  • Fig. 4 is a cross sectional view of the light guide 105 of Fig. 2 taken along line 4-4.
  • the light guide 105 receives light from at least one light source (not shown).
  • the light guide 105 illustratively receives randomly polarized light 401, 402 from a light source through surface 113.
  • the light 401 is illustratively incident on the lower surface 108 and is reflected as light 404 by the layer 107 disposed thereover.
  • dots 403 which diffusively reflect light 405.
  • light 404 and 405 are transmitted through surface 111 to the remainder of the backlight assembly components, described in connection with the example embodiments of Fig. 1.
  • the combination of the dots 403 and the layers 107 improve the uniformity and flux of the light transmitted from the light source to the display device.
  • the dots 403 are illustratively elliptical in shape and are disposed within the light guide 105. These dots are disposed on a lower surface 108 in the example embodiment, but may be disposed on other surfaces to assist in the diffusive reflection of the light from the light source or light reflected by the components of the back light assembly or the light valve.
  • the dots 403 can take other forms such as circles, rectangles, or squares.
  • the dots 403 are generally formed from a colorant that is substantially not light absorptive and has a reflectance of light greater than approximately 90%.
  • the dots 403 are screen printed with increasing density with distance from the light source to achieve uniform illuminance.
  • the dots 403 substantially diffusively reflect incident light to extract light from the light guide 105 in order to increase the efficiency and uniformity of the light transmitted to the light valve and thus the display surface.
  • the dots 403 may be microstructures such as bumps or grooves disposed over the surface(s) of the light guide. These bumps or grooves redirect light without scattering.
  • the dots 403 may be holographic optical elements (HOEs) fabricated or affixed by known techniques.
  • HOEs holographic optical elements
  • the dots 403 may be made from the material of layer 107.
  • this material may be a film, and the desired shaped dots 403 may be formed from this film.
  • the layer 107 substantially diffusively reflects incident light.
  • the material used for layer 107 is an excellent choice from which to make the dots 403.
  • the dots 403 formed from the material of layer 107 could be laminated to the bottom surface 108 of the light guide 105 in a manner similar to that used to laminate the layer 107 to other selected sides (e.g., side 110) of the light guide.
  • the dots 403 and layers 107 are useful in recycling light that is reflected back from the elements of the backlight assembly.
  • light 406 which may be polarized, is reflected back from one of the elements of the backlight assembly (e.g., the brightness enhancement layer 103, the reflective polarizer 102, or the light valve 101) and is transmitted through the surface 111 to one of the dots 403, where it is diffusively reflected as light 407.
  • Light 407 may then be reflected from the layer 107 disposed over surface 110, or may be transmitted through the surface 111. It is emphasized that light 407 is but one of the rays of the light 406 that is reflected. To wit, the diffusely reflecting dots 403 will provide light over a wide angle, such as described in connection with the reflection of light per Lambert's cosine law discussed in connection with Fig. 3. Whether the light 406 as reflected is truly Lambertian or substantially diffusively reflected, a portion of the light would otherwise be lost if not for the layer 107 disposed over the surface 108. However, some of light 406 may be diffusively reflected as light 408 by the dot 403 and traverse the air gap 120.
  • the light 408 is then diffusively reflected by the layer 107 as light 409.
  • similar reflections from the dots 403 enhance the transmission of light from the light source to the backlight assembly and the recycling of light that is reflected back from the components of the backlight assembly.
  • the arrangement of the example embodiments provides improved illumination and improved uniformity (i.e., fewer, or less severe light and dark regions at the imaging surface, or both.) at the imaging surface. For light (not shown) propagating in the plane (or near the plane) which is perpendicular to plane of the paper of Fig.4, it gets trapped in the light guide 105 if the reflective layer 107 over the surface 110 is specularly reflective.
  • the reflective layer 107 is diffusely reflective, the light that otherwise would be lost will be scattered out of the surface 111.
  • the efficiency an uniformity of the light transmitted from the light source to the light valve and thus the image surface is improved compared to known devices due to the improvement in recycling of light reflected back through surface 111 and in transmission of light from the light source 106 through the surface 111. Both of these improvements are a result of the selective incorporation of layers 107, dots 403 and the illustrative materials of which the layers 107 and dots 403 are comprised. Fig.
  • FIG. 5 is a tabular representation of the simulated performance of an illustrative light source and light guide when used in combination with a pair of crossed brightness enhancement layers 103, a polarization selective reflector 102, and an absorptive polarizer 122.
  • the source was a CCFL that provides 19.25 Lumens, and the reflective layers on the surfaces of the light guide and light source are designated in the table by reflectance (%) and reflection type, Lambertian (L) or specular (S).
  • the table includes the reflector around the CCFL 106, the reflective film underneath (e.g., disposed over surface 108) of the light guide 105 the dots 403, and the sides of the light guide that may also have a layer thereover (e.g., surfaces 110, 201 and 202). It is emphasized that there is an air gap between the bottom surface 108 and the reflective film 107.
  • the data of Fig. 5 provide comparative examples. In each example, the total flux data refer to total flux received at a plane 125 between the polarizer 122 and the light valve 101 of the same size as the light guide immediately above the polarizer 122. The total flux describes the total light efficiency.
  • the numbers in the right- most column refer to total flux received at the plane 125 only in a 5 degree cone that faces the plane 125.
  • the total flux in a 5 degree cone relates to on-axis luminance.
  • the CCFL reflector has a reflectivity of 90%.
  • the reflective layers underneath and around the sides of the light guide and dots, have a reflectivity of 90% as well.
  • the best example is found to be Example No.l, where the CCFL is specularly reflective, while the reflective layer, dots, and sides are Lambertian reflective, which results in a maximum total flux (2.34318 lumens) over the entire light guide area and a maximum total flux (0.05482 lumens) in a 5 degree cone, compared to other examples.
  • Example No.7 where all surfaces are specularly reflective. Due to light trapping in the light guide, very little light comes out (0.09122 lumens in total flux, and 0.00124 lumens in total flux in a 5 degree cone).
  • Example No. 2 is the same as Example No. 1 , except in No. 2 the CCFL reflector is a substantially Lambertian reflector.
  • Example No. 3 is the same as Example No. 1 except that the reflective layer over the sides of the light guide are specular reflectors.
  • Example No. 4 is the same as Example no. 1 except in Example No. 4 the reflective layer underneath is a specular reflector.
  • Example No. 5 is the same as Example No. 1 except in Example No. 5 the dots are specularly reflective.
  • Example No. 6 is the same as Example No. 1 except in Example No. 6 the dots and the reflective layer underneath are specularly reflective.
  • Example No. 8 is the same as Example No. 1 except in Example No. 6 the reflective layers underneath and over the sides are specularly reflective.
  • the CCFL reflector has an ideal reflectivity of 100%).
  • the reflective layers underneath and around the sides of the light guide and dots have a reflectivity of 98% as well.
  • the best example is the one with specular reflector around the CCFL, Lambertian reflector for reflective layers underneath and over the sides of the light guide, and Lambertian reflector for the dots, as represented by Example No. 11 with a maximum total flux (4.16310 lumens) over the entire light guide area and a maximum total flux (0.09525 lumens) in a 5 degree cone, compared to examples No. 9 and No. 10.
  • Example No. 9 is the same as Example No. 11 except that the reflective layer over the sides of the light guide are specular reflectors.
  • Example No. 10 is the same as Example No. 11 except that the reflective layer underneath and over the sides are specularly reflective. The comparison between Example No. 1 and No. 11 further indicates that the higher the diffusive reflectivity, the higher total flux is.
  • the numbers in the total flux are impacted by a number of factors including but not limited to followings: the shape and reflectance of the reflector 114 around the light source, the emitted flux from the light source 106, the shape, size, and material of the light guide 105, the size, shape, spacing, and reflectance of the dots, the reflectance of the reflective layers 107, the reflectance and transmittance of the polarization selective layer, the shape and material of the brightness enhancement layers. All of the above factors except those mentioned explicitly are kept unchanged in Example No.l through No. 11. As can be readily appreciated from a review of Fig. 5, the relative total flux at the top surface of the light guide is greatest when all surfaces are diffusively reflective, excepting the reflector at the light source.
  • this table shows that use of specular reflection at all surfaces provides the worst illuminance.
  • use of the diffuse reflector layer 107 over a plurality of surfaces of the light guide provides an increase in optical efficiency, relative to the use of a diffuse reflector only on the bottom surface of the light guide.
  • the use of the diffuse reflectors of the example embodiments beneath and on selected side surfaces of the light guide illustratively provides at least approximately 20% greater total flux (i.e., at least approximately 20% greater optical efficiency) than the exclusive use of specular reflectors.
  • diffuse reflectors used in the backlight assembly of a typical liquid crystal display provide an improved optical efficiency (illuminance) compared to known structures that include specular reflectors over certain surfaces of the light guide.
  • optical efficiency luminance
  • known structures that include specular reflectors over certain surfaces of the light guide.
  • the various methods, materials, components and parameters are included by way of example only and not in any limiting sense. Therefore, the embodiments described are illustrative and are useful in providing beneficial backlight assemblies. In view of this disclosure, those skilled in the art can implement the various example devices and methods to effect improved backlight efficiency, while remaining within the scope of the appended claims.

Landscapes

  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Planar Illumination Modules (AREA)
  • Optical Elements Other Than Lenses (AREA)
  • Liquid Crystal (AREA)
  • Light Guides In General And Applications Therefor (AREA)

Abstract

Il est prévu un appareil d’affichage comprenant un guide de lumière (105) ayant au moins deux surfaces sur lesquelles est disposée une couche réfléchissante à diffusion (107). De plus, un procédé de transmission de la lumière à un affichage consiste à prévoir un guide de lumière et à réfléchir de manière diffuse la lumière provenant d’au moins deux surfaces du guide de lumière. L’appareil d‘affichage peut comporter un galvanomètre à cordes à transmission (101) comme un affichage à cristaux liquides à transmission.
PCT/US2005/018613 2004-05-28 2005-05-23 Film reflechissant a diffusion pour eclairage de fond d’affichage a cristaux liquides WO2005119353A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2007515358A JP2008501149A (ja) 2004-05-28 2005-05-23 液晶ディスプレイ用拡散反射フィルム

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US10/857,515 2004-05-28
US10/857,515 US20050276073A1 (en) 2004-05-28 2004-05-28 Diffusive reflector films for enhanced liquid crystal display efficiency

Publications (1)

Publication Number Publication Date
WO2005119353A1 true WO2005119353A1 (fr) 2005-12-15

Family

ID=34971565

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2005/018613 WO2005119353A1 (fr) 2004-05-28 2005-05-23 Film reflechissant a diffusion pour eclairage de fond d’affichage a cristaux liquides

Country Status (6)

Country Link
US (1) US20050276073A1 (fr)
JP (1) JP2008501149A (fr)
KR (1) KR20070028385A (fr)
CN (1) CN1961250A (fr)
TW (1) TW200612156A (fr)
WO (1) WO2005119353A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100460897C (zh) * 2006-03-08 2009-02-11 中国科学院化学研究所 宽波长高反射率耐污染胶体光子晶体漫反射膜
EP2815270A4 (fr) * 2012-02-17 2015-10-21 3M Innovative Properties Co Guide de lumière de rétroéclairage
CN109870818A (zh) * 2019-03-12 2019-06-11 成都工业学院 一种高亮度增强现实3d显示装置及方法
CN110058348A (zh) * 2019-04-12 2019-07-26 合肥福映光电有限公司 一种应用于超窄显示模组的导光板侧边结构
US11686971B2 (en) 2020-01-19 2023-06-27 3M Innovative Properties Company Article for display device and display system

Families Citing this family (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7204630B2 (en) * 2004-06-30 2007-04-17 3M Innovative Properties Company Phosphor based illumination system having a plurality of light guides and an interference reflector
US7204631B2 (en) * 2004-06-30 2007-04-17 3M Innovative Properties Company Phosphor based illumination system having a plurality of light guides and an interference reflector
US7255469B2 (en) * 2004-06-30 2007-08-14 3M Innovative Properties Company Phosphor based illumination system having a light guide and an interference reflector
US7213958B2 (en) * 2004-06-30 2007-05-08 3M Innovative Properties Company Phosphor based illumination system having light guide and an interference reflector
US7182498B2 (en) 2004-06-30 2007-02-27 3M Innovative Properties Company Phosphor based illumination system having a plurality of light guides and an interference reflector
US20060091412A1 (en) * 2004-10-29 2006-05-04 Wheatley John A Polarized LED
KR100660707B1 (ko) * 2004-11-18 2006-12-21 엘지전자 주식회사 백라이트 유닛
PL372550A1 (pl) * 2005-02-02 2006-08-07 Skoff Spółka Z Ograniczoną Odpowiedzialnością Oprawa oświetleniowa
CN101261338B (zh) * 2007-03-06 2012-08-29 鸿富锦精密工业(深圳)有限公司 导光板制备方法
KR101391891B1 (ko) * 2007-06-22 2014-05-07 삼성디스플레이 주식회사 도광판, 이의 제조방법 및 이를 포함하는 액정 표시 장치
CN101813865A (zh) 2010-04-16 2010-08-25 鸿富锦精密工业(深圳)有限公司 电子纸显示装置
JP2013076725A (ja) * 2011-09-29 2013-04-25 Sony Corp 光源デバイスおよび表示装置、ならびに電子機器
US10502891B2 (en) * 2014-08-28 2019-12-10 Sony Corporation Display device and illumination device
KR102420965B1 (ko) * 2015-02-09 2022-07-14 삼성디스플레이 주식회사 전면 발광 장치 및 유기 발광 표시 장치
CN104820257A (zh) * 2015-04-20 2015-08-05 北京京东方茶谷电子有限公司 一种导光板、背光源和显示装置
EP3874199A4 (fr) * 2018-10-31 2022-07-13 LEIA Inc. Rétroéclairage à vues multiples, unité d'affichage, et procédé comportant des éléments de masque optique
CN113196115A (zh) * 2018-12-14 2021-07-30 3M创新有限公司 具有前侧光控膜的液晶显示器

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1994029765A1 (fr) * 1993-06-08 1994-12-22 Minnesota Mining And Manufacturing Company Affichage a cristaux liquides a luminosite amelioree
EP0898195A2 (fr) * 1992-10-09 1999-02-24 Asahi Glass Company Ltd. Dispositif d'éclairage et dispositif d'affichage à cristal liquide
US6015610A (en) * 1995-01-06 2000-01-18 W. L. Gore & Associates, Inc. Very thin highly light reflectant surface and method for making and using same
US20030169513A1 (en) * 2002-03-11 2003-09-11 Eastman Kodak Company Surface formed complex polymer lenses diffuse reflector
WO2003083530A1 (fr) * 2002-03-28 2003-10-09 Koninklijke Philips Electronics N.V. Systeme d'eclairage compact et dispositif d'affichage
US6647199B1 (en) * 1996-12-12 2003-11-11 Teledyne Lighting And Display Products, Inc. Lighting apparatus having low profile

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE69522183T2 (de) * 1994-12-16 2002-04-25 Canon Kk Beleuchtungsvorrichtung und diese enthaltende Flüssigkristallanzeige
US6497946B1 (en) * 1997-10-24 2002-12-24 3M Innovative Properties Company Diffuse reflective articles
US6390638B1 (en) * 2000-02-10 2002-05-21 Ide, Inc. Bulb wrap using expanded polytetrafluoroethylene
EP1302788B1 (fr) * 2000-07-12 2005-01-05 Toray Industries, Inc. Pellicule blanche pour elements reflecteurs de lumieres de surface
KR20040039400A (ko) * 2001-09-26 2004-05-10 코닌클리케 필립스 일렉트로닉스 엔.브이. 도파관, 가장자리-발광 조명 장치 및 이들을 포함하는디스플레이
US7192174B2 (en) * 2002-04-01 2007-03-20 Hunatech Co., Ltd. Light guiding panel formed with minute recesses by a sand blasting process and a backlight unit using the same

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0898195A2 (fr) * 1992-10-09 1999-02-24 Asahi Glass Company Ltd. Dispositif d'éclairage et dispositif d'affichage à cristal liquide
WO1994029765A1 (fr) * 1993-06-08 1994-12-22 Minnesota Mining And Manufacturing Company Affichage a cristaux liquides a luminosite amelioree
US6015610A (en) * 1995-01-06 2000-01-18 W. L. Gore & Associates, Inc. Very thin highly light reflectant surface and method for making and using same
US6647199B1 (en) * 1996-12-12 2003-11-11 Teledyne Lighting And Display Products, Inc. Lighting apparatus having low profile
US20030169513A1 (en) * 2002-03-11 2003-09-11 Eastman Kodak Company Surface formed complex polymer lenses diffuse reflector
WO2003083530A1 (fr) * 2002-03-28 2003-10-09 Koninklijke Philips Electronics N.V. Systeme d'eclairage compact et dispositif d'affichage

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN100460897C (zh) * 2006-03-08 2009-02-11 中国科学院化学研究所 宽波长高反射率耐污染胶体光子晶体漫反射膜
EP2815270A4 (fr) * 2012-02-17 2015-10-21 3M Innovative Properties Co Guide de lumière de rétroéclairage
CN109870818A (zh) * 2019-03-12 2019-06-11 成都工业学院 一种高亮度增强现实3d显示装置及方法
CN109870818B (zh) * 2019-03-12 2023-10-13 成都工业学院 一种高亮度增强现实3d显示装置及方法
CN110058348A (zh) * 2019-04-12 2019-07-26 合肥福映光电有限公司 一种应用于超窄显示模组的导光板侧边结构
US11686971B2 (en) 2020-01-19 2023-06-27 3M Innovative Properties Company Article for display device and display system

Also Published As

Publication number Publication date
US20050276073A1 (en) 2005-12-15
CN1961250A (zh) 2007-05-09
TW200612156A (en) 2006-04-16
JP2008501149A (ja) 2008-01-17
KR20070028385A (ko) 2007-03-12

Similar Documents

Publication Publication Date Title
WO2005119353A1 (fr) Film reflechissant a diffusion pour eclairage de fond d’affichage a cristaux liquides
KR100798711B1 (ko) 조광 장치 및 이를 구비한 표시 장치
US7220026B2 (en) Optical film having a structured surface with offset prismatic structures
US6829071B2 (en) Optical devices using reflecting polarizing materials
US8757858B2 (en) Hollow backlight with tilted light source
JP4487629B2 (ja) 面照明装置及びそれを用いた液晶表示装置
TWI490606B (zh) 具有梯度提取之半鏡中空背光
US7903194B2 (en) Optical element for lateral light spreading in back-lit displays and system using same
KR101277872B1 (ko) 다기능 향상 필름
TW516328B (en) Illumination device, picture display device using the same, liquid crystal television, liquid crystal monitor and liquid crystal information terminal equipment
US20110249446A1 (en) Optical element for lateral light spreading in edge-lit displays and system using same
US20100135004A1 (en) Back-lit displays with high illumination uniformity
US20060290843A1 (en) Illumination element and system using same
JP2008527627A (ja) 丸みのある構造体を備える表面を有する光学フィルム
JP2010123464A (ja) 照明装置、光学シート及び液晶表示装置
US20080037283A1 (en) Backlight apparatus with particular light-redirecting film
US20060290845A1 (en) Polarization sensitive illumination element and system using same
JP2010262813A (ja) 照明装置及び液晶表示装置
US20100141870A1 (en) Optical sheet and lcd apparatus having the same
JPH06337413A (ja) 液晶表示装置
JPH1020125A (ja) 面光源装置および液晶表示装置
JP2001194529A (ja) 光路変換偏光板

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BW BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE EG ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KM KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NA NG NI NO NZ OM PG PH PL PT RO RU SC SD SE SG SK SL SM SY TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GM KE LS MW MZ NA SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LT LU MC NL PL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
WWE Wipo information: entry into national phase

Ref document number: 1020067024923

Country of ref document: KR

Ref document number: 2007515358

Country of ref document: JP

WWE Wipo information: entry into national phase

Ref document number: 200580017326.4

Country of ref document: CN

NENP Non-entry into the national phase

Ref country code: DE

WWW Wipo information: withdrawn in national office

Country of ref document: DE

WWP Wipo information: published in national office

Ref document number: 1020067024923

Country of ref document: KR

122 Ep: pct application non-entry in european phase